With the advent of broadband networks and a mass data era, there is an increasing demand for high-bandwidth transmission, high density, and high-performance computing, and the following requirements are raised for design of a communications device system: (1) A higher bandwidth inside the device system is required, along with a capability of sustainable evolution of the high bandwidth; (2) the device system is required to have higher integration and a highly-efficient heat dissipation capability, that is, competitiveness of the system is reflected in the evolution of the high bandwidth and system integration.
For a communications device system with a shelf or cabinet structure, a PCB (Printed Circuit Board, printed circuit board) backplane is used inside the conventional device system, and a bottom-to-top straight air duct or a Z-shaped air duct is used as a heat dissipation manner of the system. Therefore, the system encounters a bottleneck in terms of high-bandwidth development and system integration improvement. A conventional high-rate PCB backplane is subject to various constraints, such as the number of backplane layers, a backplane thickness, a backplane size, backplane material quality, and backplane costs, and therefore cannot support a high-density and high-rate wiring requirement. In addition, constraints also exist in such aspects as a rate of an electrical signal and a transmission distance. For example, after a rate of a high-rate signal exceeds 10 Gbit/s, it is already quite difficult to interconnect high-rate cables on a large-sized backplane, and the problem is even more severe at 25 Gbit/s or a higher rate.
In a conventional device system solution, in terms of a cooling air duct, independent air duct space is required for the bottom-top straight air duct to evolve to the Z-shaped air duct. This reduces system space utilization and system integration, and cooling air passes a turning part of a “Z” channel, which increases wind resistance, lowers wind speed, and causes slightly low heat dissipation efficiency of the system.